#input {
  position: absolute;
  bottom: 10px;
  left: 50%;
  width: 8em;
  max-width: 80%;
  background: none;
  border: none;
  outline: none;
  border-bottom: 2px solid #fff;
  color: #fff;
  font-size: 3em;
  text-align: center;
  z-index: 999;
  opacity: .25;
  -webkit-transform: translateX(-50%);
          transform: translateX(-50%);
  transition: opacity .3s;
}
#input:hover, #input:focus {
  opacity: 1;
}

body {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;
  -webkit-user-select: none;
     -moz-user-select: none;
      -ms-user-select: none;
          user-select: none;
}